UNIVERSITY    OF   CALIFORNIA 

COLLEGE    OF   AGRICULTURE 

AGRICULTURAL    EXPERIMENT   STATION 

BERKELEY,    CALIFORNIA 


FRUIT  JUICE  CONCENTRATES 


JOHN  H.  IRISH 


BULLETIN  392 

September,  1925 


UNIVERSITY  OF  CALIFORNIA  PRINTING  OFFICE 

BERKELEY,  CALIFORNIA 

1925 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  California,  Davis  Libraries 


http://www.archive.org/details/fruitjuiceconcen392iris 


FRUIT  JUICE  CONCENTRATES 

JOHN  H.  IRISH 

of  Division  of  Viticulture  and  Fruit  Products 


The  investigations  reported  in  this  publication  supplement  those 
of  Bulletin  359,  Fruit  Beverage  Investigations,  of  this  Station.  The 
latter  gave  the  results  of  experiments  on  the  preparation  of  carbon- 
ated beverages,  while  the  present  deals  principally  with  the  prepar- 
ation of  concentrated  fruit  juices  from  which  carbonated  beverages 
and  other  products  can  be  made. 

Relation  to  the  Fruit  Industry. — Crop  reports  show  that  a  sur- 
plus of  apples,  berries,  citrus  fruits,  grapes  and  pomegranates 
frequently  exists  in  California.  This  surplus  usually  consists  of 
over-sized,  under-sized,  malformed  and  blemished  but  sound  fruit 
''culls"  which  is  not  readily  marketable  in  the  fresh  state.  The  dis- 
posal of  this  surplus  profitably  already  constitutes  one  of  the  important 
problems  of  the  fruit  industry  in  spite  of  the  fact  that  large  acreages 
of  some  of  the  fruits  have  not  yet  come  into  bearing.  This  problem  will 
probably  become  more  acute  as  production  increases.  It  is  believed 
that  the  marketing  of  surplus  fruits  in  the  form  of  concentrated 
juices  affords  a  promising  outlet  for  much  of  the  surplus,  both  present 
and  impending. 

Although  large  amounts  of  fruit  are  utilized  every  year  in  the 
manufacture  of  vinegar  and  fruit  juice  for  local  consumption,  the 
preparation  of  jams,  jellies,  preserves,  low  grade  canned  fruit,  etc., 
there  still  remains  a  large  and  growing  surplus  which  is  either  not 
utilized  or  is  often  sold  fresh  in  competition  with  and  to  the  detriment 
of  graded  fruit. 

Accurate  data  on  the  amount  of  surplus  of  all  fruits  are  not  avail- 
able. However,  a  reliable  estimate  by  the  Division  of  Subtropical 
Horticulture  has  been  obtained  for  oranges,  lemons  and  pomegranates. 
An  annual  production  of  about  96,000  tons  of  cull  oranges  and  41,000 
tons  of  cull  lemons  is  estimated.  If  a  larger  proportion  of  the  total 
crop  were  "culled"  the  growers  would  probably  realize  a  greater 
profit  from  their  good  fruit.  About  300  tons,  or  about  20  per  cent,  of 
the  pomegranate  crop  was  culled  last  year. 

It  is  estimated  that  the  average  annual  production  of  waste  apples 
in  the  United  States  is  500,000  tons  and  in  California  it  probably 
amounts  to  at  least  75,000  tons,  Cull  apples  are  at  present  utilized 
in  making  vinegar,  sweet  cider  and  evaporated  apples.  Neverthe- 
less, the  use  of  part  of  the  crop  for  concentrated  juice  for  beverage 
purposes  might  increase  the  total  returns  from  apple  culls. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


The  term  concentrates  as  used  in  this  publication  refers  to  fruit 
juices  which  have  been  concentrated  by  the  removal  of  water  either 
by  the  application  of  heat  or  by  freezing. 

If  the  juice  from  these  waste  fruits  had  been  converted  into  con- 
centrates for  use  in  carbonated  beverages  it  would  have  yielded  the 
following  amounts  of  concentrates  and  beverages  made  from  con- 
centrates : 

Possible  Yields  of  Concentrates  and  Beverages  from  Cull  Fruits 


Fruit 

Tons  of 
fruit 

Gallons  of 
concentrate 

Number  of  6^-oz. 
bottles  of 
beverage 

Value  of 
beverages  at 
5c  a  bottle2 

Value  of 
concentrates, 
approximately 

Oranges 

98,000 

41,000 

300 

260,000 

75,000 

425,000 

1,920,000 
1,000,000 
7,500 
7,812,510 
2,250,000 

12,750,000 

864,000,000 

1,476,000,000 

1,000,000 

1,000,000,000 

191,250,000 

1,083,750,000 

$43,200,000 

73,800,000 

50,000 

50,000,000 

9,562,500 

54,187,500 

1  $7,000,000 

30,000 

10,000,000 

3,000,000 

16,000,000 

Lemons 

Pomegranates 

Grapesi 

Apples,  California.. 
Apples,  U.  S.  out- 
side of  California. 

1  Includes  cull  table  grapes  and  raisins  used  for  by-products. 

2  Retail  value;  wholesale  value  probably  about  one-half  retail  value. 

The  table  does  not  include  Florida  citrus  fruits,  Hawaiian  pine- 
apples, Pacific  Coast  berries  and  cherries  of  the  Eastern  United 
States,  all  of  which  are  important  potential  sources  of  fruit  concen- 
trates. 

Relation  to  the  Beverage  Industry. — That  there  exists  a  large 
potential  market  for  surplus  fruits  in  the  form  of  concentrated  juice 
for  use  in  the  beverage  industry  is  shown  by  the  following  consider- 
ation. There  were  consumed  in  the  United  States  last  year  about 
8,000,000,000  bottles  of  carbonated  beverages  or  about  333,000,000 
cases  of  24  bottles  each.  It  cost  at  least  80c  to  produce  each  case. 
The  total  cost  to  the  bottler,  therefore,  was  not  less  than  $266,400,000. 
The  retail  value  at  $1.20  a  case  represents  a  total  of  about  $400,000,000. 
The  carbonated  beverage  industry  is  still  growing  rapidly.  If  all 
of  the  surplus  fruit  in  the  United  States  were  available  for  beverage 
purposes,  approximately  one-half  of  the  demand  for  carbonated 
beverages  could  be  met;  but  a  large  proportion  of  the  surplus  of 
various  fruits  is  not  available  for  beverage  purposes  because  it  is 
utilized  in  other  ways.  If  only  one-fourth  of  the  synthetic  carbonated 
beverages  could  be  supplanted  by  fruit  beverages  it  would  provide 
a  profitable  means  of  disposing  of  the  greater  part  of  the  present 
surplus  of  fruit. 


BULL.  392]  FRUIT    JUICE    CONCENTRATES  5 

The  bottlers  of  carbonated  beverages  now  use  synthetic  syrups 
that  permit  of  great  dilution  during  carbonating  and  bottling.  In 
order  that  their  present  equipment  might  be  used  efficiently  with 
pure  fruit  products  it  is  necessary  that  such  products  be  furnished 
in  highly  concentrated  form. 

Uses  for  Fruit  Concentrates. — Fruit  concentrates  have  a  wide 
variety  of  uses  in  the  preparation  of  beverages  and  foods.  Of  these 
the  most  important  are  carbonated  and  non-carbonated  beverages, 
jellies,  gelatin  desserts,  ice  cream,  candy  and  numerous  cooked  foods. 

Methods  of  Producing  Fruit  Concentrates. — Several  methods  have 
been  devised  for  the  concentration  of  fruit  juices.  Some  of  these  are 
not  practicable  commercially,  while  others  have  proved  satisfactory 
and  are  now  being  used  extensively  in  the  commercial  production  of 
concentrates. 

1.  Concentration  by  Heat  at  Atmospheric  Pressure. — By  this 
method  fruit  juices  are  concentrated  in  various  types  of  open  concen- 
trators, such  as  direct-fired  kettles,  sorghum  pans,  steam-heated  pans, 
steam- jacketed  kettles  and  kettles  heated  by  steam  coils.  Because  the 
delicate  flavor  and  color  of  most  fruit  juices  is  easily  injured  by  heat, 
these  methods  have  not  proved  satisfactory  in  the  production  of 
fruit  concentrates  for  use  in  the  beverage  industry.  Boiled  cider 
is  made  in  open  concentrators,  but  is  commonly  used  in  the  manufac- 
ture of  mince  meat  and  the  aroma  of  the  original  juice  is  not  required 
in  the  finished  product.  "Moskyfat, "  a  grape  product  of  South 
Africa,  consists  of  grape  juice  concentrated  in  the  open.  It  has  a 
characteristic  caramelized  flavor  and  brownish  red  color  and  although 
not  suitable  for  carbonated  beverages,  is  satisfactory  for  cooking 
purposes. 

2.  Concentration  by  Solar  Heat. — This  method  has  given  fair 
results  on  a  small  scale  but  has  not  been  adopted  commercially.  From 
the  standpoint  of  the  bottler  the  method  is  objectionable  because 
during  concentration  the  juice  is  much  oxidized  and  loses  both  its 
fresh  flavor  and  color.  It  is  only  suitable  for  concentrating  juices  for 
cooking  purposes  and  table  use. 

3.  Spray  Process. — Fruit  juice  may  be  concentratd  by  the  "spray- 
milk  drying"  process  but  usually  the  addition  of  glucose,  cane  sugar 
dextrine  or  other  "drying"  agent  is  necessary  to  prevent  the  forma- 
tion of  syrup  after  drying.  The  Merrill-Soule  Company  of  New  York 
has  successfully  reduced  orange  and  lemon  juices  to  powdered  form 
by  this  process.  The  lemon  powder  reduced  in  this  manner  is  a  fairly 
satisfactory  product  and  could  undoubtedly  be  used  in  preparing 
carbonated  beverages.     The  orange  juice  powder  samples  tested  are 


D  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

decidedly  lacking  in  flavor  and  unless  the  quality  can  be  improved 
would  not  be  very  suitable  for  beverage  purposes. 

4.  Concentration  by  Freezing. — This  process  is  the  best  for  pre- 
serving the  aroma  and  color  of  the  original  fruit.  It  has  been  studied 
by  Eudo  Monti  in  Italy  and  H.  C.  Gore  in  the  United  States.  Accord- 
ing to  Gore's  process  the  fruit  juice  is  placed  in  ice  cans  and  frozen 
to  a  solid  cake  of  ice.  The  ice  is  then  broken  up  and  placed  in  a 
centrifuge  basket  which  is  operated  at  a  moderate  speed.  The  whirl- 
ing of  the  centrifuge  forces  the  syrup  through  the  perforations  of 
the  basket  and  separates  it  from  the  ice  crystals.  By  two  or  three 
successive  freezings  and  centrifugings,  the  juice  is  concentrated  to 
50° -55°  Balling.  This  or  a  similar  method  has  been  used  successfully 
in  the  Hawaiian  Islands  for  the  concentration  of  pineapple  juice 
although  marketing  of  the  syrup  has  been  difficult. 

The  Monti  process  is  continuous  and  the  syrup  is  separated  from 
the  ice  crystals  by  draining  or  otherwise.  The  centrifuge  is  not  used. 
Professor  Eudo  Monti  states  that  this  process  is  used  commercially  in 
Italy  for  the  preparation  of  grape  syrup. 

5.  The  "Ice  Plant  Process." — In  cooperation  with  the  Lindsay 
Farm  Bureau  and  Community  Ice  Company  of  Lindsay,  I  have  been 
able  to  develop  a  process  for  concentrating  pomegranate  juice  by 
freezing  which  eliminates  several  of  the  difficulties  encountered  in 
the  other  freezing  processes.  This  process  is  applicable  to  nearly  all 
fruit  juices.     It  is  described  on  pages  11-13. 

6.  Concentration  in  Vacuo'. — Concentration  at  atmospheric  press- 
ure results  in  the  loss  of  flavor  and  color  and  often  in  caramelization. 
Some  of  these  difficulties  may  be  avoided  by  concentrating  under 
vacuum.  Under  a  vacuum,  liquids  boil  at  a  lower  temperature  than 
in  the  open  and  the  moisture  is  removed  with  less  injury  to  the  juice. 
"Vacuum  pan"  is  the  name  applied  to  the  commercial  apparatus 
utilizing  this  principle.  There  are  many  vacuum  pans  in  operation  in 
sugar  refineries,  milk  concentrating  plants  and  fruit  juice  concen- 
trating plants  in  this  state.  This  apparatus  is  the  one  most  exten- 
sively used  in  the  commercial  production  of  fruit  concentrates  at 
present. 

Vacuum  pans  vary  greatly  in  materials  of  construction  and  in  gen- 
eral design.  The  simplest  apparatus  consists  of  a  steam  jacketed, 
enclosed,  cylindrical  tank  with  curved  bottom  and  connected  through 
a  vapor  condenser  to  a  pump  which  exhausts  the  air  from  the  appa- 
ratus and  maintains  it  under  a  vacuum.  In  most  commercial  vacuum 
pans  in  addition  to  the  steam  jacket,  or  replacing  it,  are  steam  coils, 
or  a  steam  calandria  which  consists  of  vertical,  steam  jacketed  tubes 


Bull.  392 


FRUIT    JUICE    CONCENTRATES 


Fig.  1. — The  Pfaudler  Pre-heater  with  the  Pfaudler  Vacuum  Pan.     By  courtesy 
of  the  Pfaudler  Company  of  Eochester,  N.  Y. 


Condenser 


Vacuum 
Line, 


Control    Board 

with  Indejr  TlieriiioineteLy, 

Vacuum  L~  Steam  Gauges 


^:"33.™V.v.v.t::..:-.::xC:-pr 


yn~^t 


J2^ 


Vacuum 
Pump 


Vactuun    Pan  with.    HeahneS 
Coils ,  Heating  Jack.et.6-  Agitator 


Pre -heater  with 
Heating  Coils, 


Fig.    2. — Diagram    shows    "hook-up"'    of    Pfaudler    Pre-heater    with    Pfaudler 
Vacuum  Pan.     By  courtesy  of  the  Pfaudler  Company  of  Eochester,  N.  Y. 


8  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

placed  inside  the  pan.     Figure  1  is  a  glass  enameled  vacuum  equip- 
ment of  which  figure  2  is  a  diagramatic  sketch. 

In  another  type  of  vacuum  pan  the  liquid  travels  upward  by  ebulli- 
tion through  a  steam  or  hot  water  jacketed  pipe  or  series  of  pipes  and 
emerges  in  concentrated  form.  In  another  similar  apparatus  the 
liquid  travels  downward.  These  are  known  as  ascending  and  descend- 
ing film  evaporators  respectively.  In  them  the  liquid  is  subjected  to 
the  evaporating  temperature  for  a  very  short  time  only,  so  that  injury 
by  heat  is  much  reduced. 

A  very  successful  vaccum  pan  for  fruit  juices  is  that  known  as  the 
"Peebles  Evaporator."  (See  fig.  3)  In  this  apparatus  the  juice  is 
heated  to  a  relatively  high  temperature  outside  the  vacuum  pan 
proper  and  is  then  sprayed  into  the  evaporating  chamber  where  the 
great  rapidity  of  evaporation  reduces  the  temperature  of  the  juice 
instantly. 

It  will  not  be  possible  in  this  publication,  because  of  lack  of  space 
to  describe  fully  the  mechanical  features  and  operation  of  all  vacuum 
pans.  Those  who  contemplate  installing  such  equipment  will  be  fur- 
nished references  on  the  subject  and  assisted  in  other  ways  in  obtain- 
ing further  information. 

Recovery  of  Aroma, — A  large  part  of  the  aroma  of  fruit  juices 
consists  of  volatile  flavoring  compounds  which  are  readily  destroyed 
or  driven  off  by  heating,  even  in  vacuo.  It  is  possible  to  recover  a 
portion  of  these  volatile  compounds  by  collecting  the  distillate  and 
redistilling  it  at  a  higher  temperature  than  was  used  in  concentrating 
the  juice.  These  compounds  volatilize  early  in  the  concentrating 
process.  Most  of  the  aroma  volatilizes  during  the  first  few  minutes 
so  that  it  may  be  resovered  in  a  small  amount  of  the  water  distillate. 
M.  K.  Serailian  of  San  Francisco  has  developed  a  continuous  process 
by  which  the  aroma  may  be  recovered  and  returned  to  the  concentrate 
automatically. 

EEPOET   OF   INVESTIGATIONS 

In  order  to  determine  the  most  satisfactory  methods  of  preparing 
fruit  concentrates  a  series  of  experiments  have  been  conducted  in  the 
Fruit  Products  Laboratory  of  the  University  and  in  commercial  fac- 
tories during  the  past  three  years.  The  principal  results  are  reported 
in  this  publication. 

Standardization  of  Fruit  Concentrates. — Fruit  juices  from  differ- 
ent localities  from  fruit  at  different  stages  of  maturity  and  produced 
under   different   cultural   methods   vary   greatly   in   sugar   and   acid 


Bull.  392" 


FRUIT    JUICE    CONCENTRATES 


content  so  that  standardization  of  concentrates  made  from  such  juices 
demands  careful  attention.  As  a  result  of  many  experiments  and 
observations  the  following  information  was  obtained. 


Fig.  3. — A  diagramatic  sketch  of  a  Peebles  Single  Effect  Evaporator.  It 
consists  of  the  expansion  chamber  (A)  and  the  tubular  heater  (B).  The  expan- 
sion chamber  (A)  is  sealed  with  a  spring  seating  valve  (C)  and  a  centrifugal 
pump  (D),  the  latter  designed  to  operate  with  vacuum  on  the  intake  side  and 
against  pressure  on  the  discharge  side.  The  vapor  line  (E)  conducts  the  gen- 
erated vapors  to  the  condensing  system  (F),  which  also  includes  the  means  for 
creating  and  maintaining  the  vacuum.  The  inlet  (H)  is  used  for  filling  the 
expansion  chamber  (A)  and  the  outlet  (I)  permits  the  discharge  of  the  con- 
centrated material.  The  heater  (B)  is  heated  by  steam.  The  pump  (D)  is 
driven  by  motor  (G).  The  concentrating  liquor  (C  L)  enters  the  heater  (B)  at 
75°  F.  and  leaves  it  at  125°  F. 


10  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

Some  juices  such  as  apple  and  loganberry  made  from  immature 
fruit  will  jellify  when  a  concentration  of  60°  to  75°  F.  Balling  is 
reached,  which  is  objectionable  because  of  the  difficulty  of  redissolving. 
This  can  be  avoided  by  deacidifying  with  calcium  carbonate.  There 
is  danger  of  introducing  foreign  flavors  by  doing  this,  however,  and 
of  reducing  the  amount  of  dilution  that  the  juice  will  bear.  A  better 
plan  is  to  concentrate  to  only  55°  Balling  or  less. 

For  concentrated  orange  juice  a  standard  soluble  solid  (sugar) 
and  acid  ratio  of  12  to  1  at  72°  Balling  has  been  adopted  by  one 
commercial  firm.  The  slight  deficiency  in  sugar  is  made  up  by  adding 
cane  sugar. 

Lemon  juice  should  be  concentrated  to  72°  Balling  or  about  35  per 
cent  acidity.  Grape  juice  should  be  concentrated  to  67-68°  Balling 
and  preserved  by  pasteurizing  or  other  means.  Above  68°  Balling  it  is 
apt  to  crystallize.  Pomegranate  juice  should  be  concentrated  to  65° 
Balling.  A  satisfactory  pineapple  concentrate  of  75°  Balling  and  4 
per  cent  acid  has  been  used  in  these  investigations.  It  is  produced 
commercially. 

The  experiments  show  that  the  keeping  quality  of  the  color  and 
flavor  of  some  fruit  concentrates  is  improved  by  the  addition  of  cane 
sugar.  The  amount  required  varies  with  the  variety  of  juice  and 
its  composition.  The  individual  juices  are  discussed  more  fully  under 
experiments  on  "Concentration  in  Vacuo." 

Experiments  on  Concentration  in  Vacuo. — Experiments  with  this 
process  were  conducted  by  using  two  forms  of  small  glass  vacuum 
apparatus,  a  laboratory-size,  tin-plated,  copper  vacuum  pan  and  a 
glass  enamel  lined  vacuum  pan.  In  all  experiments  the  best  results 
were  obtained  in  the  glass  and  the  glass  enamel  apparatus.  The  metal 
imparted  a  metallic  taste  and  impaired  the  color  of  the  concentrate. 

One  form  of  Glass  Apparatus*  was  assembled  in  the  laboratory  on 
the  principle  of  the  descending  film  evaporator.  It  consisted  of  a  one- 
inch  outer  glass  tube  which  served  as  a  steam  jacket  and  an  inner 
1/4 -inch  tube  which  served  as  a  boiling  tube  and  which  was  connected 
at  one  end  to  the  juice  supply  and  at  the  other  to  a  receiving  flask, 
condenser  and  vacuum  pump.  While  the  capacity  was  small  the 
apparatus  gave  excellent  results  because  the  heating  period  was  short. 
(See  fig.  4.) 

All  juices  were  clarified  before  concentration.  The  difficulty  of 
filtering  highly  concentrated  juices  because  of  their  viscosity  renders 
it  necessary  to  clarify  the  juice  before  concentrating.  The  methods  of 
filtration  and  clarification  are  described  in  detail  in  Bulletin  359. 


*  Assembled  by  W.  V.  Cruess. 


Bull.  392] 


FRUIT    JUICE    CONCENTRATES 


11 


Details  of  the  vacuum  concentration  experiments  are  given  under 
the  individual  fruits,  pages  13-14. 

Experiments  on  Concentration  by  the  liIce  Plant  Process." — The 
equipment  for  these  experiments  was  that  used  in  the  commercial 
production  of  ice  at  Lindsay.  The  ice  cans,  which  were  made  of  sheet 
iron,  were  electro-plated  with  copper  in  order  to  prevent  contact  of 
the  juice  with  the  iron.  The  cans  should  be  made  of  a  metal  or  coated 
with  a  material  that  will  not  react  with  the  acid  of  the  juice,  or  injure 


*"TU5L 


JV^UT-LLT 


DDT1LATL 


TO 

VACUUM 
3^MP 


Fig.  4. — Glass  vacuum  apparatus  used  in  laboratory  experim 


ents. 


the  color  or  flavor.  Block-tin,  monel -metal,  silver  and  glass  enamel 
are  suitable  for  most  juices.  If  corrodible  metal  cans  only  are  avail- 
able, frequent  coating  with  lacquer  or  paraffiin  will  prevent  excessive 
reaction  between  the  metal  and  juice. 

The  air  agitating  device  used  in  the  manufacture  of  ice  was  placed 
in  the  bottom  of  the  can  of  juice  to  be  frozen.  Ice  formed  first  as  a 
coating  on  the  inside  of  the  can.  This  coating  increased  in  thickness 
until  most  of  the  water  of  the  juice  had  frozen  and  had  formed  a 
solid  cake  of  ice  with  a  cavity  at  the  bottom  where  the  agitation  had 
occurred.  When  the  freezing  was  complete  the  syrup  was  siphoned 
off  or  drained  from  the  ice.  The  cake  of  ice  was)  then  removed  from 
the  can  and  allowed  to  drain. 


12 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


A  concentrate  of  42°  Balling  was  obtained  by  one  freezing  of  juice 
that  was  originally  17°  Balling;  40  gallons  of  juice  yielded  12  gallons 
of  concentrate. 

The  experiment  showed  that  air  supplied  to  the  agitator  should 
be  filtered.    This  can  be  done  by  enclosing  the  intake  in  a  dust-proof 


Fig.   5. — Ice  making  tanks. 


By   courtesy   of  Automatic   Kefrigerator   Company, 
Hartford,  Conn. 


box,  filled  with  a  filtering  medium.  In  dry,  dusty  weather,  without 
this  precaution  sufficient  dust  would  be  carried  by  the  air  into  the 
juice  to  render  it  unfit  for  human  consumption. 

The  Lindsay  community  ice  plant  has  a  capacity  of  nine  tons  of 
ice  in  24  hours.  At  full  capacity  the  plant  is  capable  of  concentrating 
the  juice  of  30  tons  of  pomegranates  a  day  if  full  efficiency  were 
realized. 


Bull.  392]  FRUIT    JUICE    CONCENTRATES  13 

Since  many  of  the  fruits  suitable  for  juice  are  available  in  the 
fall  and  winter  when  the  demand  for  ice  is  light,  the  ice  making 
equipment  might  be  used  for  the  concentration  of  fruit  juices  with 
very  little  additional  expense. 

It  is  very  probable  that  the  adaptation  of  ice  manufacturing  equip- 
ment to  the  production  of  concentrates  can  be  made  decidedly  profit- 
able, largely  because  it  would  utilize  the  equipment  during  the  idle 
season. 

The  concentrates  should  be  stored  in  hermetically  sealed  contain- 
ers in  freezing  storage  if  it  is  desired  to  retain  the  full  flavor  and 
color.  Concentrates  prepared  experimentally  have  been  preserved  for 
several  months  with  fair  success  by  pasteurization  at  175°  F.,  but 
after  prolonged  storage  loss  of  color  and  flavor  are  apt  to  occur.  See 
also  page  18  on  "Preservation  of  Fruit  Concentrates." 

CONCENTRATING  VAEIOUS   FRUIT  JUICES 

1.  Grape.— For  use  in  beverages  the  most  important  classes  of 
grapes  are  those  having  a  strong  distinctive  flavor  such  as  the  Muscat 
and  the  Semillon,  those  of  deep  color  but  mild  flavor  such  as  the 
Alicante  Bouschet  and  Petite  Sir  ah  and  those  of  combined  deep  color 
and  distinctive  flavor  such  as  the  Pierce  and  Concord. 

Concentrates  were  produced  from  the  three  classes.  Juices  of  from 
22°  to  24°  Balling,  in  optimum  condition  for  the  purpose,  were 
concentrated  to  72°  Balling  in  vacuo.  A  blend  of  two  parts  of  the 
concentrate  of  high  flavor  with  one  part  of  the  color  variety  gave  a 
syrup  that  made  an  excellent  carbonated  beverage  on  dilution  with 
carbonated  water.  It  was  found  that  the  acidity  of  grape  concen- 
trates was  low  owing  to  the  precipitation  of  the  cream  of  tartar.  This 
deficiency  may  be  made  up  by  the  addition  of  tartaric  acid  in  amounts 
sufficient  to  meet  the  requirements  of  the  product  in  which  the  con- 
centrate is  to  be  used.  Pierce  grape  concentrate  was  fairly  satisfac- 
tory although  much  of  the  flavor  was  lost  by  ordinary  vacuum  pan 
concentration. 

2.  Apple. — Apple  juice  of  14°  Balling  and  .5  per  cent  acid  was 
concentrated  in  vacuo  to  60°  Balling.  This  was  found  to  be  the  best 
of  the  experimental  apple  concentrates  for  beverage  purposes. 

3.  Pomegranate. — Pomegranate  juice  was  concentrated  in  glass 
in  vacuo  to  72°  Balling  and  reduced  to  70°  Balling  by  the  addition 
of  the  redistilled  condensate  containing  the  aroma.  While  satisfac- 
tory for  coloring  other  juices  the  pomegranate  used  alone  lacked 
flavor. 


14  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

4.  Berries. — Using-  the  glass  and  glass  enamel  vacuum  apparatus, 
blackberry  and  loganberry  juices  were  concentrated  to  50°  Balling 
and  strawberry  juice  to  60°  Balling.  Concentrated  blackberry  juice 
was  not  found  suitable  for  use  in  beverages  because  of  the  lack  of  dis- 
tinctive flavor  while  the  strawberry  was  deficient  in  color.  However, 
when  two  parts  of  strawberry  concentrate  and  one  part  of  blackberry 
were  combined,  a  beverage  with  a  good  strawberry  flavor  and  a  bright 
red  color  was  obtained  on  dilution  with  water. 

The  loganberry  possessed  sufficient  flavor  and  color  of  its  own  when 
bottled  with  carbonated  water.  While  not  equal  to  beverages  made 
from  the  fresh  juices  those  from  the  concentrated  juices  were  very 
satisfactory.  If  prepared  for  sale,  the  blended  blackberry  and  straw- 
berry products  would  require  on  the  label  some  such  statement  as 
"strawberry  with  blackberry." 


EXPERIMENTS  ON  THE  UTILIZATION  OF  FRUIT  CONCENTRATES 

Fruit  concentrates  can  be  easily  transported  and  preserved  for 
use  in  the  manufacture  of  many  products. 

1.  Bottled  Carbonated  Beverages. — This  is  probably  the  largest 
outlet  for  fruit  concentrates  since  they  are  especially  suitable  for  this 
purpose,  and  because  the  market  has  already  been  partially  developed. 

a.  Orange,  has  proved  the  most  popular  and  is  the  most  extensively 
used  of  all  fruit  concentrates  for  beverage  purposes.  In  our  experi- 
ments a  bottlers  syrup  was  prepared  according  to  the  following 
formula : 

1  gallon  72°  Balling  concentrate  (prepared  commercially  at  San 
Dimas,  California). 

5  gallons  60°  Balling  simple  sj^rup  (cane  sugar  and  water). 

7V2  c.c  orange  oil  (cold  pressed  California  oil). 

l1/^  ozs.  of  this  syrup  was  added  to  each  6%-oz.  bottle  and  carbon- 
ated water  added  under  low  pressure. 

Orange  requires  low  carbonation  to  produce  the  most  palatable 
drink  and  one  volume  of  gas  was  found  sufficient.  The  carbonated 
bottled  beverage  was  successfully  pasteurized  at  150°  F.,  in  30  minutes 
and  has  retained  its  flavor  and  color  very  well  in  all  cases  for  two 
months  and  in  some  cases  much  longer. 

b.  Lemon,  because  of  its  high  acidity  and  distinctive  flavor,  was 
found  one  of  the  most  satisfactory  of  all  fruit  concentrates  tested 
and  permitted  of  the  greatest  dilution.  The  following  formula  was 
found  best : 


Bull.  392]  FRUIT    JUICE    CONCENTRATES  15 

1  gallon  72°  Balling  concentrate  (from  a  commercial  factory  at 
San  Dimas). 

20  gallons,  60°  Balling  simple  syrup. 

20  c.c  lemon  oil  (cold  pressed  California  oil). 

1%  ozs.  of  this  syrup  was  added  to  each  6Mi-oz.  bottle  and  carbon- 
ated 2  to  3  volumes  of  gas. 

It  also  withstood  pasteurization  and  retained  its  flavor  for  several 
months.  The  finished  beverage  is  cloudy  and  on  standing  develops 
a  slight  deposit,  but  this  readily  goes  into  suspension  on  lightly  shak- 
ing the  bottle.  The  Henry  Brown  Co.  of  Glendale  and  the  Imperial 
Soda  Works  of  Oakland  are  successfully  bottling  both  the  lemon  and 
the  orange  beverages  prepared  in  the  above  or  a  similar  manner. 

c.  Grape.  The  sugar  content  of  grape  concentrate  was  so  high  that 
it  did  not  require  the  addition  of  simple  syrup  and  was  used  according 
to  the  following  formula: 

1  gallon  72°  Balling  red  grape  concentrate  for  color; 

2  gallons  72°  Balling  Muscat  concentrate  for  flavor;  both  juices 
concentrated  in  vacuo  at  the  Fruit  Products  Laboratory.  The  syrups 
were  mixed  thoroughly  and  1  oz.  wras  added  to  each  G1/^-02-  bottle  and 
carbonated  with  3  volumes  of  gas.  When  the  carbon  dioxide  dirl  not 
produce  sufficient  tartness  the  deficiency  was  made  up  by  adding  the 
required  amount  of  tartaric  acid. 

This  product  was  sold  under  the  name  of  ' '  Muscat  Blend ' '  to  the 
campus  public  and  was  well  received  over  a  period  of  more  than  a 
year. 

d.  Apple.  Like  grape,  apple  did  not  require  the  addition  of  sim- 
ple syrup. 

1%  ozs.  of  60°  Balling  apple  concentrate  was  added  to  each  6!/2- 
oz.  bottle  and  then  filled  with  water  carbonated  with  3  volumes  of 
gas.  This  produced  a  very  fine  beverage  which  withstood  pasteuriza- 
tion and  retained  the  quality  perfectly  during  storage  in  the  bottle. 

The  concentrate  was  prepared  in  the  Fruit  Products  Laboratory 
from  cull  Newtown  Pippin  apples  by  the  usual  juice  extraction 
methods,  filtration,  and  concentration  in  a  glass-lined  vacuum  pan. 

e.  Pomegranate.  This  was  not  found  satisfactory  for  carbonated 
beverage.    A  still  beverage  was  made  as  follows  : 

1  gallon  70°  Balling  concentrate. 

4  gallons  of  water. 

7%  lbs.  sugar. 

This  was  bottled  in  Qy2-oz.  bottles  and  pasteurized  at  175°  F.,  for 
30  minutes.  It  has  retained  its  color  and  flavor  very  well  and  pro- 
duces on  dilution  an  excellent  drink.  The  syrup  was  made  by  pressing 
the  whole  fruit,  heating  to  175°  F.,  cooling  24  hours,  filtering  and 
concentrating  in  vacuo  in  glass. 


16  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

/.  A  strawberry-blackberry  beverage  was  made  as  follows  from 
concentrates  prepared  in  the  Fruit  Products  Laboratory : 

2  gallons  60°  Balling  strawberry  concentrate; 

1  gallon  50°  Balling  blackberry  concentrate;  both  syrups  made  by 
concentration  in  vacuo. 

9  gallons  60°  Balling  simple  syrup. 

1%  ozs.  of  this  syrup  was  added  to  each  6%-oz.  bottle  and  filled 
with  water  carbonated  with  3  volumes  of  gas.  The  bottled  beverage 
was  pasteurized  at  150°  F.,  for  30  minutes  and  has  retained  its 
original  quality  in  a  satisfactory  manner. 

g.  A  loganberry  beverage  was  made  as  follows : 

1  gallon  50°  Balling  loganberry  concentrate  made  by  concen- 
tration in  a  glass-lined  vacuum  pan. 

5  gallons  60°  Balling  simple  syrup. 

1%  ozs.  of  this  syrup  was  added  to  each  QYo-oz.  bottle  and  filled 
with  water  carbonated  with  3  volumes  of  gas. 

h.  Cherry  concentrate  was  prepared  from  ripe  Black  Tartarian 
cherries  by  crushing  the  fruit,  heating  to  212°  F.,  on  the  pits,  pressing, 
filtering  and  concentrating  in  a  glass-lined  vacuum  pan  to  65°  Balling. 
It  was  used  in  several  ways  but  was  found  best  according  to  the  follow- 
ing formula: 

1  gallon  60°  Balling  cherry  concentrate. 
5  gallons  60°  Balling  simple  syrup. 

10  c.c.  bitter  almond  oil. 

1%  ozs-  of  this  syrup  was  added  to  each  6%-oz.  bottle  and  water 
carbonated  with  3  volumes  of  gas  added  to  fill  the  bottles. 

Note:  All  carbonated  fruit  beverages  require  pasteurization  for 
30  minutes  at  150°  F.,  or  the  addition  of  y1{)  of  1  per  cent  sodium 
benzoate  for  preservation. 

In  addition  to  the  formulae  given  many  others  were  tested.  Those 
listed  were  found  best. 

2.  Fruit  Concentrates  for  Punch. — The  great  acidity  of  lemon 
concentrate  renders  it  suitable  for  blending  with  other  fruit  concen- 
trates to  be  used  for  making  punch.  In  one  case  it  was  combined  with 
orange  and  blackberry  according  to  the  following  formula.* 

2  gallons  72°  Balling  commercial  lemon  concentrate. 
1  gallon  72°  Balling  commercial  orange  concentrate. 

1  gallon  50°  Balling  blackberry  concentrate  (from  laboratory 
experiments). 

25  c.c  lemon  oil  (cold  pressed,  California). 

The  composition  of  this  blend  was  66°  Balling  and  22  per  cent  total 
acidity  as  citric.    It  was  found  to  keep  without  pasteurization  because 


*  Such  a  blend  was  just  suggested  and  prepared  by  W.  V.  Cruess  in  July,  1924. 


BULL.  392]  FRUIT    JUICE    CONCENTRATES  17 

of  the  high  acidity  but  for  safety  in  preparing  it  for  sale  it  has  been 
pasteurized  at  175°  F.,  for  30  minutes.  It  withstands  pasteurizing 
and  storage  fairly  well. 

Punch  was  prepared  from  this  syrup  as  follows : 

1  gallon  punch  concentrate. 
20  gallons  water. 
30  lbs.  sugar. 

Individual  taste  varies;  some  consumers  prefer  greater  dilution, 
some  less.  The  concentrate  has  been  sold  to  numerous  campus  organ- 
izations and  to  many  Berkeley  families.  It  has  proved  very  popular. 
A  company  in  Los  Angeles  is  now  producing  it  and  others  are  inter- 
ested. 

Pomegranate  punch  concentrate  was  prepared  as  follows  : 

1  gallon  72°  Balling  commercial  lemon  concentrate. 
4   gallons    72°    Balling    pomegranate    concentrate    (made    in    the 
laboratory). 

Punch  was  prepared  according  to  the  following  formula : 

1  gallon  pomegranate  punch  concentrate. 
20  gallons  water. 
15  lbs.  sugar. 

The  drink  was  of  excellent  purplish  red  color,  and  good  flavor ;  it 
was  even  superior  to  the  blackberry-orange-lemon  blend.  Pomegranates 
are  plentiful  and  cheap.  The  writer  believes  this  blend  has  great 
commercial  possibilities. 

Many  other  combinations  are  possible  and  a  number  of  these  have 
been  prepared.     One  of  these  is  lemon-red  grape-orange. 

3.  Sherberts,  Water  Ices  and  Ice  Cream. — Fruit  concentrates  were 
found  especially  satisfactory  for  use  in  sherbets  and  water  ices. 
Either  a  small  quantity  of  the  concentrate  may  be  added  to  the 
sherbet  stock  or  it  may  be  diluted  to  about  the  strength  of  the  original 
juice,  sweetened  when  necessary  and  frozen.  The  color  and  flavor  of 
the  original  juice  is  preserved  in  the  finished  product. 

A  delicious  fruit  flavored  ice  cream  was  produced  by  adding 
various  concentrates  to  vanilla  ice  cream  in  sufficient  amount  to  impart 
the  characteristic  flavor  of  the  fruit.  This  work  was  conducted  in  the 
ice  cream  plant  of  the  Dairy  Division  at  Davis  by  Professor  G.  D. 
Turnbow  and  the  writer.  A  more  complete  joint  report  will  be  made 
later  on  the  use  of  fruits  in  this  form  and  other  forms  in  ice  cream. 

4.  In  Candy. — James  B.  Vance,  a  former  graduate  student  assist- 
ant in  this  laboratory  found  that  concentrated  berry  juices  could  be 
used  successfully  in  preparing  jellied  fruit  candy  with  sugar  and 
pectin. 


18  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

A.  Roewade,  former  chief  chemist  for  the  Remar  Candy  Company, 
used  berry  concentrates  successfully  for  flavoring  cream  centers  for 
chocolate  dipping.  Other  possible  uses  for  fruit  concentrates  in  candy 
are  flavoring  and  coloring  marshmallows,  gum  drops,  fruit  drops,  etc. 

5.  For  Jelly. — The  concentrates  have  been  used  in  the  laboratory 
as  a  base  for  jellies.  They  were  diluted  with  water;  pectin  and  siugar 
were  added  and  the  mixture  cooked  to  the  jellying  point.  Very  good 
jelly  resulted.  This  suggested  their  use  in  the  household  with  any 
of  the  household  pectins  now  on  the  market  to  prepare  jelly  at  any 
season  of  the  year.  It  might  also  provide  a  means  of  supplying  com- 
mercial jelly  makers  remote  from  fruit-growing  sections,  with  jelly 
bases  from  all  suitable  varieties  of  fruit. 

Preservation  of  Fruit  Concentrates. — Fruit  juices  concentrated  to 
72°  Balling  do  not  spoil  readily  at  moderate  temperatures  because 
most  micro-organisms  cannot  live  in  juice  of  such  high  concentration. 
However,  molding  may  sometimes  occur  in  nearly  all  concentrates  and 
fermentation  in  some.  Some  means  of  preservation  is,  therefore, 
desirable. 

1.  Cold  Storage. — Tests  made  show  that  concentrates  can  be  held 
indefinitely  without  spoilage  in  cold  storage  at  30°  F.  It  is  advisable, 
however,  to  seal  the  concentrates  in  glass,  wooden  or  properly  coated 
metal  containers  so  that  the  absorption  of  odors  and  tastes  is  avoided. 
The  containers  must  not  be  filled  completely  because  expansion  during 
freezing  would  cause  breakage.  Concentrates  have  been  stored  experi- 
mentally in  this  manner  for  more  than  a  year  without  noticeable  loss 
of  color  or  flavor.    It  is  to  be  preferred  to  pasteurization. 

2.  Pasteurization. — If  concentrates  are  to  be  held  indefinitely,  sub- 
jected to  moderately  high  temperatures,  pasteurization  will  prevent 
spoiling.  In  experiments  in  this  laboratory  pasteurizing  at  175°  F., 
for  the  following  times  varying  according  to  the  size  of  the  container 
was  found  effective : 

4-oz.  bottle  20  minutes 

6-oz.   bottle 25  minutes 

Pint  bottle 30  minutes 

Quart  bottle  35  minutes 

%-gallon  bottle  45  minutes 

Gallon  bottle  60  minutes 

These  pasteurizing  times  and  temperatures  were  determined  by 
extensive  heat  penetration  studies. 

Directions  for  pasteurization  are  given  in  detail  in  Bulletin  359 
and  Circular  220  of  this  station. 


BULL.  392]  FRUIT    JUICE    CONCENTRATES  19 

These  publications  will  be  sent  free  on  application  to  the  College 
of  Agriculture,  Berkeley. 

3.  Chemical  Preservatives. — Shipment  of  concentrates  to  hot 
climates  often  necessitates  the  use  of  a  chemical  preservative.  This  is 
particularly  necessary  for  barrel  shipments.  Sodium  benzoate  is  used 
for  this  purpose  and  is  permissible  when  its  presence  is  stated  on  the 
label.  State  regulations  vary  regarding  the  use  of  preservatives  and 
the  regulations  of  the  states  into  which  the  product  is  to  be  shipped 
should  be  studied  and  must  be  observed.  The  usual  limit  is  %o  of 
1  per  cent  although  some  states,  California  among  them,  permit  the 
use  of  more  than  Y10  of  1  per  cent  provided  it  is  declared  on  the  label. 

Only  chemically  pure  sodium  benzoate  of  the  best  quality  should 
be  used.  It  should  be  free  from  odors  of  other  drugs  such  as  iodoform, 
creosote,  etc.,  which  impart  very  disagreeable  tastes  to  the  products. 
It  is  used  at  the  rate  of  5  ozs.  of  dry  sodium  benzoate  dissolved  in  a 
small  amount  of  water,  to  every  47  gallons  of  concentrate  or  20  ozs. 
by  weight  of  a  25  per  cent  solution. 

COMMERCIAL  PRODUCTION 

Companies  have  been  and  are  being  organized  for  the  produc- 
tion of  fruit  concentrates,  while  several  established  sweet  cider  com- 
panies are  expanding  and  preparing  to  produce  a  full  line  of  fruit 
concentrates.  Several  bottlers  of  carbonated  beverages  have  under- 
taken the  bottling  of  carbonated  fruit  beverages  which  require  fruit 
concentrates.  The  use  of  fruit  concentrates  in  carbonated  beverages, 
therefore,  is  rapidly  emerging  from  the  experimental  stage  and  their 
commercial  development  appears  to  be  certain.  This  laboratory  is  in 
active  touch  with  the  principal  producers  of  fruit  concentrates  and 
is  cooperating  with  them  to  place  the  products  on  a  successful  com- 
mercial basis. 

SUMMARY  AND  CONCLUSIONS 

1.  Fruit  juices  in  concentrated  form  are  more  satisfactory  than 
the  non-concentrated  juices  for  use  in  the  commercial  production  of 
carbonated  beverages,  sherbets,  water  ices,  candy  and  other  products 
owing  to  saving  in  transportation  and  convenience  in  handling. 

2.  Our  experiments  have  showed  that  excellent  concentrates  may 
be  made  from  the  juice  of  oranges,  lemons,  grapes,  pomegranates, 
apples,  raspberries,  loganberries  and  blackberries.  Strawberry  con- 
centrate lacked  color  but  this  deficiency  was  made  up  by  the  addition 
of  blackberry  concentrate. 


20  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

3.  Concentration  by  freezing  was  found  to  be  the  best  method  for 
the  preservation  of  the  color  and  flavor  of  the  fresh  juice  but  did  not 
yield  so  high  a  concentration  as  vacuum  concentration. 

4.  Concentration  in  vacuo  in  a  glass-lined  vacuum  pan  was  found 
to  be  the  most  practical  method  for  concentrating  all  juices  that  were 
studied. 

5.  The  aroma  of  the  fresh  juice  lost  during  concentration  may  be 
recovered  from  the  condensate  by  redistillation  and  may  then  be 
returned  to  the  concentrate. 

6.  Test  sales  to  consumers  and  observations  on  recent  commercial 
developments  indicate  that  carbonated  beverages  made  from  fruit 
juice  concentrates  will  find  a  large  market. 

7.  The  difference  in  the  consistency  of  various  juices  renders  it 
impracticable  to  establish  a  standard  of  concentration  to  which  all 
juices  can  be  made  to  conform.  However,  it  is  possible  to  establish 
reasonably  narrow  limits  for  each  individual  fruit.     This  is  desirable. 

8.  Lemon  concentrate  because  of  its  great  acidity  is  excellent  for 
combining  with  other  fruit  concentrates  for  fruit  punch  concentrate 
to  be  used  in  soda  fountains,  in  bottling  works  and  in  the  home. 

9.  Concentrates  should  be  stored  in  sealed  containers  to  prevent 
the  absorption  of  disagreeable  odors  when  cold  storage  is  used  as  a 
means  of  preservation. 

10.  Several  methods  of  preservation  are  available.  A  concentrate 
of  72°  Balling  will  keep  several  weeks  at  ordinary  temperatures  with- 
out spoiling.  Cold  storage  at  a  temperature  of  32°  F.,  or  lower  will 
preserve  it  indefinitely. 

If  concentrates  are  to  be  shipped  to  tropical  climates  in  containers 
that  may  permit  infection  with  yeast  or  mold,  sodium  benzoate  should 
be  used  as  a  preservative. 

Pasteurization  at  175°  F.,  is  a  safe  means  of  preserving  fruit 
concentrates  but  storage  at  room  temperature  results  in  some  loss  of 
color  and  change  in  flavor. 

11.  Experiments  and  observations  indicate  that  the  preparation  of 
fruit  concentrates  may  provide  an  outlet  for  much  of  the  state's 
surplus  fruits. 


15m-9,'25 


